Simplify your plumbing and home improvement projects with the John Guest Union Connector. The John Guest 5/16 inch OD x 1/4 inch OD reducing union connector is manufactured from durable white polypropylene and equipped with EPDM o-rings that utilize John Guest's push-fit technology to make easy, reliable, leak-free connections. These connectors have been developed to satisfy the compatibility needs of a wide range of applications and can be used on plastic or soft copper tubing. Push-to-connect fittings provide a simple, quick, reliable, and leak-free connection with no tools required. FDA-compliant material; NSF 61 and 51 certified